Changing the internal switch clock (this is done to change the redemption date, upon the wondercard redemption) is advised against. You can safely change the date on PKHeX.
Anyways, HOME didn't check the met date legality for any events, so far.
@Marie Shiomi @theSLAYER
Stupid me already updated the plugin to NET9 ... sorry!
Use the previous version (2.2.2), it still works fine on PKHeX 24.11.11.
Update to v2.3 once PKHeX is on NET9.
WC3Plugin-2.2.2.zip